Methods have been developed to separate cell types comprising the caput epididymidis using unit gravity sedimentation. To definatively identify the cell types contained within the fractions eluted from the sedimentation gradient, electron micrographs will be made of cells from separations of hamster, rat and rabbit caput epididymal tissue. The homogeneity of cell types contained within each fraction will be ascertained in part from the electron micrographs and partly by differential staining techniques which we hope to develop. Attempts will be made to define optimum conditions for culture of each separated cell type. Cells will be evaluated for viability and normalcy of biochemical parameters as well as maintenance of characteristic morphology. Commercially available media will be tested after supplementation with different levels of fetal calf serum and combinations of hormones.